Impact of major stroke service centralisation on mortality and care: analysis of admissions, interventions and outcomes in South Australia.

BACKGROUND

Major system reform is complex but can yield improved outcomes at multiple levels. We aimed to evaluate the impact of implementing a hub and spoke model of stroke care across metropolitan Adelaide (population 1.2 million), South Australia on mortality, morbidity, service and quality stroke indicators.

METHODS

Analysis of 24 months of prospectively collected, patient-level data covering all metropolitan stroke admissions during the contiguous pre-, during- and post-implementation time periods, linked to mortality data from the National Death Index. The three metropolitan tertiary hospital-based stroke units undertook the implementation of a centralised 'hub and spoke' model: one central comprehensive stroke centre offering 24 h stroke reperfusion therapies, and two primary stroke centres providing 12 h thrombolysis. The main outcome measures were mortality (any cause) up to 180 days post-admission; reperfusion treatment proportions and timings; stroke care quality composite metric; length of stay.

RESULTS

There were 3917 confirmed stroke admissions over the 24-month period (3325 (84.9%) ischaemic) and 650 deaths (19.6%) within 180 days. Compared to the baseline period, post-intervention mortality and discharge disability did not differ, although a possible temporary increase in ischaemic stroke mortality during implementation was seen. Rates of endovascular thrombectomy (EVT) (5.7% vs. 12.5%, adjusted Rate Ratio (aRR) = 1.94, 95%CI 1.21,3.10) and timeliness of EVT (median 126 min (IQR 83, 154) vs. 95 min (53, 132), p < 0.001) improved as did the composite stroke quality metric indicator (0.60, 95% CI 0.50, 0.70 vs. 0.64, 95% CI 0.50, 0.75; adjusted difference 0.041, 95% CI 0.015, 0.066). Length of stay decreased for ischaemic stroke (8.2 (SD 12.4) vs. 7.9 (SD 8.9) days, adjusted geometric mean ratio = 0.83, 95% CI 0.73. 0.94) but not for intracerebral haemorrhage.

CONCLUSION

The major implementation of a metropolitan centralised 'hub and spoke' model of acute stroke care was associated with overall significant improvements in process indicators but a possible temporary increase in ischaemic stroke mortality during implementation.